This invention concerns new processes for the polymerization of olefins using as a polymerization catalyst a nickel complex of certain 2-aminotropones. Also described are novel compounds that are the complexes and intermediates for making the complexes, as well as processes for producing such compounds.
Polymers of ethylene and other olefins are important items of commerce, and these polymers are used in a myriad of ways, from low molecular weight polyolefins being used as a lubricant and in waxes, to higher molecular weight grades being used for fiber, films, molding resins, elastomers, etc. In most cases, olefins are polymerized using a catalyst, often a transition metal compound or complex. These catalysts vary in cost per unit weight of polymer produced, the structure of the polymer produced, the possible need to remove the catalyst from the polyolefin, the toxicity of the catalyst, etc. Due to the commercial importance of polymerizing olefins, new polymerization catalysts are constantly being sought.
Arylaminotropones are useful as chemical intermediates, for instance in the synthesis of pharmaceuticals and pesticides.
Nickel complexes of various neutral ligands and mono-anionic ligands are known as catalysts for the polymerization of ethylene and other olefins, see for instance (for monoanionic ligands) U.S. Pat. No. 6,060,569, WO9830609 (corresponding to U.S. patent application Ser. No. 09/006536, filed Jan. 13, 1998, now U.S. Pat. No. 6,174,975) and WO9842664, which are incorporated by reference herein for all purposes as if fully set forth. None of these references describe the use of aminotropones as ligands for nickel containing olefin polymerization catalysts.
Anilinotropones, especially 2-anilinotropones, have been made by a variety of methods, see for instance K. Kikuchi, Bull. Chem. Soc. Jpn., vol. 51, p. 2338 (1978); T. Nozoe, Bull. Chem. Soc. Jpn., vol. 51, p. 2185 (1978); and W. R. Brasen, J. Am. Chem. Soc., vol. 83, p. 3125 (1961). The methods described in these references are different from the methods described herein. In addition, yields of the desired 2-anilinotropones are generally lower than reported herein, and/or sterically hindered less basic arylamines are not used in the synthesis thereof.
One aspect of the present invention concerns a first process for the polymerization of olefins, comprising the step of contacting, at a temperature of about xe2x88x92100xc2x0 C. to about +200xc2x0 C., one or more olefins with an active catalyst comprising a nickel complex of an anion of the formula 
wherein:
R2 is hydrocarbyl or substituted hydrocarbyl, provided that R2 is attached to said nitrogen atom in (I) by an atom that has at least 2 other atoms that are not hydrogen attached to it; and
R3, R4, R5, R6 and R7 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, provided that any two of R3, R4, R5, R6 and R7 vicinal to one another may form a ring.
Another aspect of the present invention concerns a second process for the polymerization of olefins, comprising the step of contacting, at a temperature of about xe2x88x92100xc2x0 C. to about +200xc2x0 C., one or more olefins with a compound of the formula 
wherein:
R2 is hydrocarbyl or substituted hydrocarbyl, provided that R2 is attached to said nitrogen atom in (I) by an atom that has at least 2 other atoms that are not hydrogen attached to it;
R3, R4, R5, R6 and R7 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, provided that any two of R3, R4, R5, R6 and R7 vicinal to one another may form a ring;
L1 is a monodentate monoanionic ligand into which an olefin molecule may insert between L1 and the nickel atom, and L2 is an empty coordination site or a monodentate neutral ligand which may be displaced by an olefin, or L1 and L2 taken together are a monoanionic bidentate ligand into which an olefin may insert between said monoanionic bidentate ligand and the nickel atom;
and provided that when L1 and L2 taken together are 
then a cocatalyst is also present.
In the above-mentioned processes, (II) and/or the nickel complex of (I) may in and of themselves be active catalysts, or may be xe2x80x9cactivatedxe2x80x9d by contact with a cocatalyst/activator, as exemplified by the case when L1 and L2 taken together are (I).
The present invention also concerns a compound of the formula 
wherein:
R2 is hydrocarbyl or substituted hydrocarbyl, provided that R2 is attached to said nitrogen atom in (I) by an atom that has at least 2 other atoms that are not hydrogen attached to it; and
R3, R4, R5, R6 and R7 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, provided that any two of R3, R4, R5, R6 and R7 vicinal to one another may form a ring;
L1 is a monodentate monoanionic ligand, and L2 is a monodentate neutral ligand or an empty coordination site, or L1 and L2 taken together are a monoanionic bidentate ligand.
Another aspect of the present invention is a process for making 2-arylamino substituted tropones, comprising the step of contacting, in solution at a temperature of about 20xc2x0 C. to about 150xc2x0 C., a first compound of the formula 
a second compound of the formula HNR9R19 (IV), a palladium compound, a base capable of deprotonating said second compound, and a third compound which is a mono- or diphosphine in which all of the bonds to phosphorous are to carbon atoms, wherein:
R3, R4, R5, R6 and R7 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, provided that any two of R3, R4, R5, R6 and R7 vicinal to one another may form a ring;
R8 is a group such that the conjugate acid of xe2x80x94OR8 has a pKa of  less than 0 in water at 20xc2x0 C.;
R19 is hydrocarbyl, substituted hydrocarbyl or hydrogen; and
R9 is aryl or substituted aryl.
Still another aspect of the present invention is a compound of the formula 
wherein:
R3, R4, R5, R6 and R7 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, provided that any two of R3, R4, R5, R6 and R7 vicinal to one another may form a ring; and
R11, R12, R13, R14 and R15 are each independently hydrogen, hydrocarbyl substituted hydrocarbyl or a functional group, provided that any two of R11, R12, R13, R14 and R15 vicinal to one another taken together may form a ring; provided that:
both of R11 and R15 are not hydrogen; and/or
the total of the Hammett a constants for R11, R12, R13,
R14 and R15 is about 0.50 or more; and/or
an ES for one or both of R11 and R15 is xe2x88x920.10 or less.
A further aspect of the present invention is an anion of the formula 
wherein:
R2 is hydrocarbyl or substituted hydrocarbyl, provided that R2 is attached to said nitrogen atom in (I) by an atom that has at least 2 other atoms that are not hydrogen attached to it; and
R3, R4, R5, R6 and R7 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, provided that any two of R3, R4, R5, R6 and R7 vicinal to one another may form a ring.
Herein, certain terms are used. Some of them are:
A xe2x80x9chydrocarbyl groupxe2x80x9d is a univalent group containing only carbon and hydrogen. As examples of hydrocarbyls may be mentioned unsubstituted alkyls, cycloalkyls and aryls. If not otherwise stated, it is preferred that hydrocarbyl groups herein contain 1 to about 30 carbon atoms.
By xe2x80x9csubstituted hydrocarbylxe2x80x9d herein is meant a hydro-carbyl group that contains one or more substituent groups which are inert under the process conditions to which the compound containing these groups is subjected. The substituent groups also do not substantially interfere with the process. If not otherwise stated, it is preferred that substituted hydrocarbyl groups herein contain 1 to about 30 carbon atoms. Included in the meaning of xe2x80x9csubstitutedxe2x80x9d are heteroaromatic rings. When a heteroaromatic ring is present, it may be attached to another group through the heteroatom. In substituted hydrocarbyl all of the hydrogens may be substituted, as in trifluoromethyl.
By xe2x80x9c(inert) functional groupxe2x80x9d herein is meant a group other than hydrocarbyl or substituted hydrocarbyl which is inert under the process conditions to which the compound containing the group is subjected. The functional groups also do not substantially interfere with any process described herein that the compound in which they are present may take part in. Examples of functional groups include halo (fluoro, chloro, bromo and iodo), ether such as xe2x80x94OR22 wherein R22 is hydrocarbyl or substituted hydrocarbyl. In cases in which the functional group may be near a nickel atom the functional group should not coordinate to the metal atom more strongly than the groups in those compounds are shown as coordinating to the metal atom, that is they should not displace the desired coordinating group.
By xe2x80x9colefinxe2x80x9d is meant a compound containing one or more olefinic double bonds. In the event that the compound contains more than one olefinic double bond, they should be non-conjugated. As examples of olefins may be mentioned cyclopentene, a styrene, a norbornene, and compounds of the formulas R17CHxe2x95x90CH2 wherein R17 is hydrogen or alkyl.
By an oligomerization or polymerization xe2x80x9cco-catalystxe2x80x9d or xe2x80x9ccatalyst activatorxe2x80x9d is meant a compound that reacts with a transition metal compound to form an activated catalyst species. A preferred catalyst activator is an xe2x80x9calkyl aluminum compoundxe2x80x9d, that is, a compound which has at least one alkyl group bound to an aluminum atom. Other groups such as alkoxide, hydride, and halogen may also be bound to aluminum atoms in the compound.
By xe2x80x9cneutral Lewis basexe2x80x9d is meant a compound, which is not an ion, that can act as a Lewis base. Examples of such compounds include ethers, amines, sulfides, and organic nitriles.
By xe2x80x9cneutral Lewis acidxe2x80x9d is meant a compound, which is not an ion, that can act as a Lewis acid. Examples of such compounds include boranes, alkylaluminum compounds, aluminum halides, and antimony [V] halides.
By xe2x80x9ccationic Lewis acidxe2x80x9d is meant a cation that can act as a Lewis acid. Examples of such cations are sodium and silver cations.
By an xe2x80x9cempty coordination sitexe2x80x9d is meant a potential coordination site on a metal atom that does not have a ligand bound to it. Thus if an olefin molecule (such as an ethylene molecule) is in the proximity of the empty coordination site, the olefin molecule may coordinate to the metal atom.
By a xe2x80x9cligand into which an olefin molecule may insertxe2x80x9d between the ligand and a nickel atom is meant a ligand coordinated to the nickel atom into which an olefin molecule or a coordinated olefin molecule (such as an ethylene molecule or a coordinated ethylene molecule) may insert to start or continue a polymerization. For instance, this may take the form of the reaction (wherein L is a ligand): 
By a xe2x80x9cligand which may be displaced by an olefinxe2x80x9d is meant a ligand coordinated to a transition metal, which when exposed to an olefin (such as ethylene) is displaced as the ligand by the olefin.
By a xe2x80x9cmonoanionic ligandxe2x80x9d is meant a ligand with one negative charge.
By a xe2x80x9cneutral ligandxe2x80x9d is meant a ligand that is not charged. xe2x80x9cAlkyl groupxe2x80x9d and xe2x80x9csubstituted alkyl groupxe2x80x9d have their usual meaning (see above for substituted under substituted hydrocarbyl). Unless otherwise stated, alkyl groups and substituted alkyl groups preferably have 1 to about 30 carbon atoms.
By a xe2x80x9cstyrenexe2x80x9d herein is meant a compound of the formula 
wherein R43, R44, R45, R46 and R47 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, all of which are inert in the polymerization process. It is preferred that all of R43, R44, R45, R46 and R47 are hydrogen. Styrene (itself) is a preferred styrene.
By a xe2x80x9cnorbornenexe2x80x9d is meant ethylidene norbornene, dicyclopentadiene, or a compound of the formula 
wherein R40 is hydrogen or hydrocarbyl containing 1 to 20 carbon atoms. It is preferred that R40 is hydrogen or alkyl, more preferably hydrogen or n-alkyl, and especially preferably hydrogen. The norbornene may be substituted by one or more hydrocarbyl, substituted hydrocarbyl or functional groups in the R40 or other positions, with the exception of the vinylic hydrogens, which remain. Norbornene (itself), dimethyl endo-norbornene-2,3-dicarboxylate, t-butyl 5-norbornene-2-carobxylate are preferred norbornenes and norbornene (itself) is especially preferred.
By a xe2x80x9cxcfx80-allyl groupxe2x80x9d is meant a monoanionic ligand with 3 adjacent sp2 carbon atoms bound to a metal center in an xcex73 fashion. The three sp2 carbon atoms may be substituted with other hydrocarbyl groups or functional groups.
By xe2x80x9carylxe2x80x9d is meant a monovalent aromatic group in which the free valence is to the carbon atom of an aromatic ring. An aryl may have one or more aromatic rings which may be fused, connected by single bonds or other groups.
By xe2x80x9csubstituted arylxe2x80x9d is meant a monovalent aromatic group substituted as set forth in the above definition of xe2x80x9csubstituted hydrocarbylxe2x80x9d. Similar to an aryl, a substituted aryl may have one or more aromatic rings which may be fused, connected by single bonds or other groups; however, when the substituted aryl has a heteroaromatic ring, the free valence in the substituted aryl group can be to a heteroatom (such as nitrogen) of the heteroaromatic ring instead of a carbon.
The polymerizations herein are carried out by a nickel complex of anion (I). In (I), and in all complexes and compounds containing (I) or its parent conjugate acid, it is preferred that:
R3, R4, R5, R6 and R7 are all hydrogen; and/or
R2 is aryl or substituted aryl, especially phenyl or substituted phenyl.
Useful groups for R2 include, for example 
which may be substituted in any or all of their ring positions. It is preferred that at least one position next to (ortho) the free valence of the aryl ring be substituted, and more preferred that both of these positions be substituted. In particular it is more preferred that R2 is 
wherein each of R11, R12, R13, R14 and R15 are independently hydrogen, hydrocarbyl substituted hydrocarbyl or a functional group, provided that any two of R11, R12, R13, R14 and R15 vicinal to one another taken together may form a ring. In one particularly preferred form both R11 and R15 are not hydrogen, and/or R12, R13 and R14 are hydrogen. In another preferred form R11 and R15 are each independently chosen from the group consisting of alkyl containing 1 to 6 carbon atoms, perfluoroalkyl, alkoxy, phenyl and halo, more preferably alkyl containing 1 to 4 carbon atoms, phenyl and halo. Particularly preferred are when R11 and R13 are both i-propyl or phenyl, or when R11 is methyl and R15 is trifluoromethyl. Preferred specific groups (VI) are shown in Table 1.
All of the complexes of (I) can be made from the corresponding tropone 
In turn (VII) can be made by the process described below, using a palladium catalyst in the presence of a phosphine compound.
In a process to make (VII) the appropriately substituted arylamine, (IV) (and preferred substitution is the same as in (I)), is reacted with an appropriately substituted tropone ester (and preferred substitution is as in (I)), in the presence of a base, a palladium compound and a mono- or diphosphine. This reaction is carried out in solution, although not all of the ingredients must be totally soluble at all times, all of the starting materials, except the base, should be at least somewhat soluble. Preferred solvents are relatively inert to all of the ingredients and products, and include hydrocarbon solvents such as toluene, and ethers such as 1,4-dioxane, ethyl ether and tetrahydrofuran.
The palladium compound may be a Pd[II] compound or a Pd[0] compound, such as palladium acetate, PdX2 wherein each X is independently halogen, and palladium bis(dibenzylideneacetone), which is preferred. The phosphine may be a mono- or diphosphine in which all three of the bonds to phosphorous are to separate carbon atoms. It is preferred that the phosphine be somewhat sterically hindered. Useful phosphines include (o-tolyl)3P, (t-Bu)3P, 1,1xe2x80x2-bis(diphenylphosphino)ferrocene, bis(2-diphenylphosphinophenyl)ether, 2-(di-t-butylphosphino)biphenyl, 2-(dicylohexylphosphino)biphenyl, and 
wherein each R10 is independently aryl or substituted aryl and preferably all of R10 are phenyl (this compound is sometimes abbreviated xe2x80x9cBINAPxe2x80x9d). A preferred phosphine is (XI).
The base may be any metal salt, preferably an alkali metal salt, which can serve as an acceptor for the proton liberated from the arylamine during the process. The base should have at least sparing solubility in the process solvent. Useful bases include alkali metal carbonates such as cesium carbonate, alkali metal phosphates such as potassium phosphate (K3PO4), alkali metal alkoxides such as potassium t-butoxide, and alkali metal amides such as sodium hexamethyldisilamide.
In the process to make (VII) ratios of the various ingredients are not critical, but to make efficient and economical use of the various ingredients, it is preferred that:
the molar ratio of (III):(IV) is about 0.1 to about 1.0, more preferably about 0.8 to about 0.9;
the amount of gram-atoms of palladium (in whatever form the Pd is added) is about 0.01 to about 10 percent of the number of moles of tropone, more preferably about 0.5 to 1.5 percent; and/or
the number of equivalents of base to moles of tropone is preferably about 1.0 to about 4.0, more preferably about 1.2 to about 1.6.
The process to make (VII) is preferably carried out at a temperature of about 20xc2x0 C. to about 150xc2x0 C., more preferably about 50xc2x0 C. to about 120xc2x0 C., and especially preferably about 70xc2x0 C. to about 90xc2x0 C. It is preferred to carry out the process in the absence of water (and other active hydrogen compounds) and oxygen, especially in the absence of oxygen. This is conveniently carried done by carrying out the process under an inert gas such as nitrogen or argon. The time required for this process is also not critical, 3 to 48 hours, more typically 12-15 hours, being useful ranges.
In the process to make (VII), (III) is one of the starting materials. In (III), R8 is a group such that the conjugated acid of R8Oxe2x80x94 has a pKa of  less than 0. Useful groups for R8 include R16SO2xe2x80x94, wherein R16 is perfluorohydrocarbyl, especially perfluoroalkyl, and p-tolyl. A preferred group for R8 is R16SO2xe2x80x94, wherein R16 is perfluoroalkyl, especially trifluoromethyl (sometimes called the xe2x80x9ctriflatexe2x80x9d group). (III) may be made by methods known in the art, for instance the preparation of 2-triflatotropone is found in A. M. Echavarren, et al., J. Am. Chem. Soc., vol. 110, p. 1557 (1988), which is included by reference herein.
The process to make (VII) (and hence (X)) herein produces these types of compounds in improved yields and/or allows the production of compounds which cannot be produced by simple nucleophilic displacements, for instance using aromatic amines (IV) in which the amine group is sterically hindered by substitution at one or both of the ortho positions, and/or the amine has reduced bascisity because the aromatic group bears electron withdrawing substituents.
In (IV) (and in any of the arylaminotropones subsequently produced) it is preferred that R19 is alkyl, substituted alkyl or hydrogen, more preferred that it is alkyl or hydrogen, and especially preferred that it is hydrogen.
The steric effect of various groupings has been quantified by a parameter called ES, see R. W. Taft, Jr., J. Am. Chem. Soc., vol. 74, p. 3120-3128 (1952), and M. S. Newman, Steric Effects in Organic Chemistry, John Wiley and Sons, New York, 1956, p. 598-603, both of which are hereby incorporated by reference herein for all purposes as if fully set forth. For the purposes herein, the ES values are those for o-substituted benzoates described in these publications. If the value for ES for any particular group is not known, it can be determined by methods described in these publications. For the purposes herein, the value of hydrogen is defined to be the same as for methyl (0.00). Representative values for ES are (taken from Table V in Taft and Series 2-2 through 2-10 in Newman) xe2x80x94OCH3 +0.97, xe2x80x94Br +0.01, xe2x80x94I xe2x88x920.20, CH3CH2xe2x80x94 0.07, CH3CH2CH2xe2x80x94 xe2x88x920.36, i-C3H7xe2x80x94 xe2x88x920.47, t-C4H9xe2x80x94 xe2x88x921.54, C6H5xe2x80x94 xe2x88x920.90. In one preferred form of (X) the ES for either of the ortho substituents is xe2x88x920.10 or less, preferably about xe2x88x920.25 or less, and especially preferably about xe2x88x920.50 or less.
Another preferred form of (X) is when the phenyl ring has electron withdrawing groups attached to it. The electron withdrawing ability of various substituents may be measured by the Hammett constant, see for instance H. H. Jaffe, Chem. Rev., vol. 53, p. 191-261 (1953), especially Table 7, which is hereby included by reference. Since Hammett substituents constants are often not calculated for ortho substituents, for any ortho substituent the Hammett constant will be taken as the Hammett para constant ("sgr"para). The total of all the "sgr" constants for all of the substituents on the phenyl ring is about 0.50 or more, more preferably about 0.75 or more.
It is also preferred in (I) (and in compounds in which it occurs) that provided that one or more of the following obtains: both of R11 and R15 are not hydrogen; the total of the Hammett "sgr" constants for R11, R12, R13, R14 and R15 is about 0.50 or more; and an ES for one or both of R11 and R15 is xe2x88x920.10 or less. The more preferred forms for (X) are also preferred in (I).
Herein (VII) may be converted to a nickel complex such as (II), and in turn (II) may be active in and of itself and thus useful directly as an olefin polymerization catalyst, or may be converted to an active polymerization catalyst by contact with one or more other compounds (so-called cocatalysts). Thus (VII) may be converted to its anion by reaction with a strong base such as sodium hydride, and this anion (which is actually (I)) may be reacted with an appropriate nickel compound to form (II). Useful nickel compounds include:
(Ph3P)2Ni(Ph)(Cl) (see Example 13) which gives (II) in which L1 is Ph, and L2 is Ph3P;
(TMEDA)2Ni(Ph)(Cl) in the presence of a xe2x80x9ctrapping ligandxe2x80x9d L2 such as pyridine, which specifically gives (IX) for instance in which L1 is Ph, and L2 is pyridine; (Ph3P)2NiCl2 which gives (II) in which L1 is Cl, and L2 is Ph3P; and
((allyl)Ni(X))2 which gives (II) in which L1 and L2 taken together are xcfx80-allyl.
Methods of synthesis of these types of nickel complexes may also be found in previously incorporated U.S. Pat. No. 6,060,569, WO98/30609 and WO98/42664, and R. H. Grubbs., et al., Organometallics, vol. 17, p. 3149 (1988), which is also incorporated by reference herein for all purposes as if fully set forth.
In (II) useful groups L1 include halide (especially chloride), hydrocarbyl and substituted hydrocarbyl especially phenyl and alkyl and particularly phenyl, methyl, hydride and acyl. Useful groups for L2 include phosphine such as triphenylphosphine, nitrile such as acetonitrile, ethers such as ethyl ether, pyridine, and tertiary alkylamines such as TMEDA (N,N,Nxe2x80x2,Nxe2x80x2-tetramethyl-1,2-ethylenediamine). Alternatively L1 and L2 taken together may be a xcfx80-allyl or xcfx80-benzyl group such as 
wherein R is hydrocarbyl.
In (II) when an olefin (such as ethylene) may insert between L1 and the nickel atom, and L2 is an empty coordination site or is a ligand which may be displaced by an olefin (such as ethylene), or L1 and L2 taken together are a bidentate monoanionic ligand into which an olefin (such as ethylene) may be inserted between that ligand and the nickel atom, (II) may by itself catalyze the polymerization of an olefin. Examples of L1 into which an olefin (and particularly ethylene) may insert between it an the nickel atom are hydrocarbyl and substituted hydrocarbyl especially phenyl and alkyl and particularly methyl, hydride and acyl, and ligands L2 which an olefin (and particularly ethylene) may displace include phosphine such as triphenylphosphine, nitrile such as acetonitrile, ether such as ethyl ether, pyridine, and tertiary alkylamines such as TMEDA. Ligands in which L1 and L2 taken together are a bidentate monoanionic ligand into which an olefin (and particularly ethylene) may insert between that ligand and the nickel atom include xcfx80-allyl- or xcfx80-benzyl-type ligands (in this instance, sometimes it may be necessary to add a neutral Lewis acid cocatalyst such as triphenylborane to initiate the polymerization, see for instance previously incorporated WO98/30609). For a summary of which ligands an olefin (and particularly ethylene) may insert into (between) the ligand and nickel atom) see for instance J. P. Collman, et al., Principles and Applications of Organotransition Metal Chemistry, University Science Book, Mill Valley, Calif., 1987, included herein by reference. If for instance L1 is not a ligand into which an olefin (such as ethylene) may insert between it and the nickel atom, it may be possible to add a cocatalyst which may convert L1 into a ligand which will undergo such an insertion. Thus if L1 is halo such as chloride or bromide, or carboxylate, it may be converted to hydrocarbyl such as alkyl by use of a suitable alkylating agent such as an alkylaluminum compound, a Grignard reagent or an alkyllithium compound. It may be converted to hydride by used of a compound such as sodium borohydride.
In (II) when L1 and L2 taken together are (I), in the polymerizations a cocatalyst (sometimes also called an activator) which is an alkylating or hydriding agent is also present in the olefin polymerization. It is preferred however that L1 and L2 taken together are not (I). A preferred cocatalyst is an alkylaluminum compound, and particularly preferred are trialkylaluminum compound such as trimethylaluminum, triethylaluminum and tri-i-butylaluminum, and trimethylaluminum is especially preferred. More than one such cocatalyst may be used in combination.
In the polymerizations herein homo- or copolymers of the various olefins may be produced. A preferred olefin (or combination of olefins) is R17CHxe2x95x90CH2 wherein R17 is hydrogen or n-alkyl containing 1 to 15 carbon atoms, and especially preferred is when R17 is hydrogen or methyl (ethylene or propylene, respectively), and more preferred is when R17 is hydrogen (ethylene).
In the polymerization processes herein, the temperature at which the polymerization is carried out is about xe2x88x92100xc2x0 C. to about +200xc2x0 C., preferably about xe2x88x9260xc2x0 C. to about 150xc2x0 C., more preferably about xe2x88x9220xc2x0 C. to about 100xc2x0 C. The pressure of the olefin (if it is a gas) at which the polymerization is carried out is not critical, atmospheric pressure to about 275 MPa being a suitable range. Generally speaking the response of the catalyst, and hence the polymer produced, to the effects of temperature and pressure are similar to other nickel catalysts, see for instance U.S. Pat. No. 5,880,241 (incorporated by reference herein for all purposes as if fully set forth). As shown in Table 3 as the temperature increases catalyst productivity increases until about 80xc2x0 C. (at least under these particular polymerization conditions and this catalyst) and then starts decreasing, and the branching level increases as the temperature increases. Up to a point at least, increasing the ethylene pressure (Table 4) increases catalyst productivity, decreases branching, and increases polymer molecular weight. It is also believed that as the ethylene pressure increases, it becomes more important that the ethylene used be of high purity. The effect of catalyst loading (Table 5) is somewhat uncertain since in Example 54 there was a large exotherm.
The polymerization processes herein may be run in the presence of various liquids, particularly aprotic organic liquids. The catalyst system, monomer(s), and polymer may be soluble or insoluble in these liquids, but obviously these liquids should not prevent the polymerization from occurring. Suitable liquids include alkanes, cycloalkanes, selected halogenated hydrocarbons and aromatic hydrocarbons. Specific useful solvents include hexane, toluene, benzene, chlorobenzene, tetrahydrofuran, methylene chloride and 1,2,4-trichlorobenzene. The effects of various solvents on the polymerizations are shown in Table 7.
Various polar compounds such as ethyl acetate, triethylamine, water and ethanol may be present in the polymerization, although in some instances the yields may be reduced (see Table 6). The polymerization may also be carried out in the presence of air. It is noted that the polymerization proceeds with some of these additives even though they may contain active hydrogen atoms (water, ethanol).
The olefin polymerizations herein may also initially be carried out in the xe2x80x9csolid statexe2x80x9d by, for instance, supporting the nickel compound on a substrate such as silica or alumina, activating if necessary it with one or more cocatalysts and contacting it with the olefin(s). Alternatively, the support may first be contacted (reacted) with a cocatalyst (if needed) such as an alkylaluminum compound, and then contacted with an appropriate Ni compound. The support may also be able to take the place of a Lewis or Bronsted acid, for instance, an acidic clay such as montmorillonite, if needed. Another method of making a supported catalyst is to start a polymerization or at least make a nickel complex of another olefin or oligomer of an olefin such as cyclopentene on a support such as silica or alumina. These xe2x80x9cheterogeneousxe2x80x9d catalysts may be used to catalyze polymerization in the gas phase or the liquid phase. By gas phase is meant that a gaseous olefin is transported to contact with the catalyst particle.
In all of the polymerization processes described herein oligomers and polymers of the various olefins are made. They may range in molecular weight from oligomeric olefins, to lower molecular weight oils and waxes, to higher molecular weight polyolefins. One preferred product is a polymer with a degree of polymerization (DP) of about 10 or more, preferably about 40 or more. By xe2x80x9cDPxe2x80x9d is meant the average number of repeat (monomer) units in a polymer molecule.
Depending on their properties, the polymers made by the processes described herein are useful in many ways. For instance if they are thermoplastics, they may be used as molding resins, for extrusion, films, etc. If they are elastomeric, they may be used as elastomers. If they contain functionalized monomers such as acrylate esters, they are useful for other purposes, see for instance previously incorporated U.S. Pat. No. 5,880,241.
Depending on the process conditions used and the polymerization catalyst system chosen, polymers, even those made from the same monomer(s) may have varying properties. Some of the properties which may change are molecular weight and molecular weight distribution, crystallinity, melting point, and glass transition temperature. Except for molecular weight and molecular weight distribution, branching can affect all the other properties mentioned, and branching may be varied (using the same nickel compound) using methods described in previously incorporated U.S. Pat. No. 5,880,241.
It is known that blends of distinct polymers, that vary for instance in the properties listed above, may have advantageous properties compared to xe2x80x9csinglexe2x80x9d polymers. For instance it is known that polymers with broad or bimodal molecular weight distributions may be melt processed (be shaped) more easily than narrower molecular weight distribution polymers. Thermoplastics such as crystalline polymers may often be toughened by blending with elastomeric polymers.
Therefore, methods of producing polymers which inherently produce polymer blends are useful especially if a later separate (and expensive) polymer mixing step can be avoided. However in such polymerizations one should be aware that two different catalysts may interfere with one another, or interact in such a way as to give a single polymer.
In such a process the Ni containing polymerization catalyst disclosed herein can be termed the first active polymerization catalyst. Monomers useful with these catalysts are those described (and also preferred) above. A second active polymerization catalyst (and optionally one or more others) is used in conjunction with the first active polymerization catalyst. The second active polymerization catalyst may be another late transition metal catalyst, for example as described in previously incorporated WO98/30609, U.S. Pat. No. 5,880,241 and U.S. Pat. No. 6,060,569, as well as in U.S. Pat. No. 5,714,556 and U.S. Pat. No. 5,955,555, which are also incorporated by reference herein for all purposes as if fully set forth.
Other useful types of catalysts may also be used for the second active polymerization catalyst. For instance so-called Ziegler-Natta and/or metallocene-type catalysts may also be used. These types of catalysts are well known in the polyolefin field, see for instance Angew. Chem., Int. Ed. Engl., vol. 34, p. 1143-1170 (1995), EP-A-0416815 and U.S. Pat. No. 5,198,401 for information about metallocene-type catalysts, and J. Boor Jr., Ziegler-Natta Catalysts and Polymerizations, Academic Press, New York, 1979 for information about Ziegler-Natta-type catalysts, all of which are incorporated by reference herein for all purposes as if fully set forth. Many of the useful polymerization conditions for all of these types of catalysts and the first active polymerization catalysts coincide, so conditions for the polymerizations with first and second active polymerization catalysts are easily accessible. Oftentimes the xe2x80x9cco-catalystxe2x80x9d or xe2x80x9cactivatorxe2x80x9d is needed for metallocene or Ziegler-Natta-type polymerizations. In many instances the same compound, such as an alkylaluminum compound, may be used as an xe2x80x9cactivatorxe2x80x9d for some or all of these various polymerization catalysts.
In one preferred process described herein the first olefin(s) (the monomer(s) polymerized by the first active polymerization catalyst) and second olefin(s) (the monomer(s) polymerized by the second active polymerization catalyst) are identical, and preferred olefins in such a process are the same as described immediately above. The first and/or second olefins may also be a single olefin or a mixture of olefins to make a copolymer. Again it is preferred that they be identical particularly in a process in which polymerization by the first and second active polymerization catalysts make polymer simultaneously.
In some processes herein the first active polymerization catalyst may polymerize a monomer that may not be polymerized by said second active polymerization catalyst, and/or vice versa. In that instance two chemically distinct polymers may be produced. In another scenario two monomers would be present, with one polymerization catalyst producing a copolymer, and the other polymerization catalyst producing a homopolymer, or two copolymers may be produced which vary in the molar proportion or repeat units from the various monomers. Other analogous combinations will be evident to the artisan.
In another variation of this process one of the polymerization catalysts makes an oligomer of an olefin, preferably ethylene, which oligomer has the formula R70CHxe2x95x90CH2, wherein R70 is n-alkyl, preferably with an even number of carbon atoms. The other polymerization catalyst in the process them (co)polymerizes this olefin, either by itself or preferably with at least one other olefin, preferably ethylene, to form a branched polyolefin. Preparation of the oligomer (which is sometimes called an xcex1-olefin) by a second active polymerization-type of catalyst can be found in previously incorporated U.S. Pat. No. 5,880,241 as well as U.S. Pat. No. 6,103,946 (also incorporated by reference for all purposes as if fully set forth).
Likewise, conditions for such polymerizations, using catalysts of the second active polymerization type, will also be found in the appropriate above mentioned references.
Two chemically different active polymerization catalysts are used in this polymerization process. The first active polymerization catalyst is described in detail above. The second active polymerization catalyst may also meet the limitations of the first active polymerization catalyst, but must be chemically distinct. For instance, it may have a different transition metal present, and/or utilize a different type of ligand and/or the same type of ligand which differs in structure between the first and second active polymerization catalysts. In one preferred process, the ligand type and the metal are the same, but the ligands differ in their substituents.
Included within the definition of two active polymerization catalysts are systems in which a single polymerization catalyst is added together with another ligand, preferably the same type of ligand, which can displace the original ligand coordinated to the metal of the original active polymerization catalyst, to produce in situ two different polymerization catalysts.
The molar ratio of the first active polymerization catalyst to the second active polymerization catalyst used will depend on the ratio of polymer from each catalyst desired, and the relative rate of polymerization of each catalyst under the process conditions. For instance, if one wanted to prepare a xe2x80x9ctoughenedxe2x80x9d thermoplastic polyethylene that contained 80% crystalline polyethylene and 20% rubbery polyethylene, and the rates of polymerization of the two catalysts were equal, then one would use a 4:1 molar ratio of the catalyst that gave crystalline polyethylene to the catalyst that gave rubbery polyethylene. More than two active polymerization catalysts may also be used if the desired product is to contain more than two different types of polymer.
The polymers made by the first active polymerization catalyst and the second active polymerization catalyst may be made in sequence, i.e., a polymerization with one (either first or second) of the catalysts followed by a polymerization with the other catalyst, as by using two polymerization vessels in series. However it is preferred to carry out the polymerization using the first and second active polymerization catalysts in the same vessel(s), i.e., simultaneously. This is possible because in most instances the first and second active polymerization catalysts are compatible with each other, and they produce their distinctive polymers in the other catalyst""s presence. Any of the processes applicable to the individual catalysts may be used in this polymerization process with 2 or more catalysts, i.e., gas phase, liquid phase, continuous, etc.
Catalyst components which include Ni complexes of (I), with or without other materials such as one or more cocatalysts and/or other polymerization catalysts are also disclosed herein. For example, such a catalyst component could include the Ni complex supported on a support such as alumina, silica, a polymer, magnesium chloride, sodium chloride, etc., with or without other components being present. It may simply be a solution of the Ni complex, or a slurry of the Ni complex in a liquid, with or without a support being present.
The polymers produced by this process may vary in molecular weight and/or molecular weight distribution and/or melting point and/or level of crystallinity, and/or glass transition temperature and/or other factors. For copolymers the polymers may differ in ratios of comonomers if the different polymerization catalysts polymerize the monomers present at different relative rates. The polymers produced are useful as molding and extrusion resins and in films as for packaging. They may have advantages such as improved melt processing, toughness and improved low temperature properties.
Hydrogen or other chain transfer agents such as silanes (for example trimethylsilane or triethylsilane) may be used to lower the molecular weight of polyolefin produced in the polymerization process herein. It is preferred that the amount of hydrogen present be about 0.01 to about 50 mole percent of the olefin present, preferably about 1 to about 20 mole percent. When liquid monomers (olefins) are present, one may need to experiment briefly to find the relative mounts of liquid monomers and hydrogen (as a gas). If both the hydrogen and monomer(s) are gaseous, their relative concentrations may be regulated by their partial pressures.
In the Examples, all pressures are gauge pressures. Branching was determined by 1H NMR, taking the total of the methyl carbon atoms as the number of branches. Branching is uncorrected for end groups. The following abbreviations are used:
BINAPxe2x80x94see compound (XI)
dbaxe2x80x94dibenzylideneacetone
EtOAcxe2x80x94ethyl acetate
EtOHxe2x80x94ethanol
Mnxe2x80x94number average molecular weight
Mpxe2x80x94melting point
NEt3xe2x80x94triethylamine
PDIxe2x80x94weight average molecular weight/number average molecular weight
PhClxe2x80x94chlorobenzene
RTxe2x80x94room temperature
THFxe2x80x94tetrahydrofuran
Tmxe2x80x94melting point